1. (noun)angstrom, angstrom unit, A a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation Synonyms: antiophthalmic factor, adenine, axerophthol, vitamin A, group A, ampere, angstrom, angstromunit, deoxyadenosine monophosphate, amp, type A
2. (noun)vitamin A, antiophthalmic factor, axerophthol, A any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes Synonyms: antiophthalmic factor, adenine, axerophthol, vitamin A, group A, ampere, angstrom, angstromunit, deoxyadenosine monophosphate, amp, type A